In article , Nick Maclaren
writes

| Ah well at least one of the plants I saw last year had seeds.
| I did get three seeds from an early set pod (with permission) but they
| didn't germinate.

I think that you will find that it is NOT I. indica. In fact, I am
surprised at that Web page, because at least most forms are much darker


I am now totally confused as I have seen pictures of the darker flowers
on the web and in books and also pictures of the baby/sky blue colour I
saw last year. Could there be different strains of this then?
The Ipomea in Swallowfield had set what looked like early seed pods and
I planted them but nothing germinated.

With reference to David's question about size, the flowers are much
bigger than the normal Ipomea but I am terrible at guessing dimensions
I'm afraid. I would have said they were at least an inch and a half on
average, bigger than the normal plants.

I shall do what someone suggested and contact Waterperry's again and ask
if they can tell me. Maybe I was unlucky with the person I spoke to last
year.

Thanks to everyone for their help.
--
Janet Tweedy
Amersham Gardening Association
http://www.amersham-gardening.net

This is the nearest I have seen to the flowers appearance. I do note
however that the buds are clearly darker in colour so presumably these
flowers change as they open and possibly as they fade?
Can't tell the size though very well. Don't remember the white being so
prominent but again maybe plants vary?
http://flora.huh.harvard.edu/FloraDa...laceae/Convolv
ulaceae-Ipomoea%20alba-107.jpg

Janet
--
Janet Tweedy
Dalmatian Telegraph
http://www.lancedal.demon.co.uk

In article ,
Janet Tweedy writes:
|
| I am now totally confused as I have seen pictures of the darker flowers
| on the web and in books and also pictures of the baby/sky blue colour I
| saw last year. Could there be different strains of this then?
| The Ipomea in Swallowfield had set what looked like early seed pods and
| I planted them but nothing germinated.

Given that David has confirmed my memory, if it has seed pods, it is
NOT I. indica. No ifs or buts. I. indica does not set seed.

There are something like 500 species, of which at least half a dozen
are in cultivation and will grow outside in the UK during the summer;
quite possibly, several of the others will, too. The cultivars of
the commonly grown species (see below) are very variable in size and
colour, so odds on it is one of them.

There has been a fair amount of botanical renaming, too, and I have
never worked out what the situation is between I. nil, I. purpurea,
I. triloba (a synonym of I. nil?) and I. tricolor. I believe that
there are also hybrids. I can state definitely that there is a HELL
of a lot of confusion on the Web and in books over this, and even
quite respectable books conflict badly with each other, so I am in
good company.


Regards,
Nick Maclaren.

In message , Nick Maclaren
writes

In article ,
Janet Tweedy writes:
|
| I am now totally confused as I have seen pictures of the darker flowers
| on the web and in books and also pictures of the baby/sky blue colour I
| saw last year. Could there be different strains of this then?
| The Ipomea in Swallowfield had set what looked like early seed pods and
| I planted them but nothing germinated.

Given that David has confirmed my memory, if it has seed pods, it is
NOT I. indica. No ifs or buts. I. indica does not set seed.

I found a claim in Am. J. Bot. That I. indica is self-incompatible. If
this is correct then it is possible that it does set seed in the wild,
but that the cultivated stock is a single clone. (For comparison,
Lavatera 'Bicolor' is resolutely sterile in normal cultivation, but does
produce seed when grown alongside Lavatera acerifolia. I want to obtain
wild-collected seed of Lavatera maritima to test the nature of Lavatera
'Bicolor' further.)

There are something like 500 species, of which at least half a dozen
are in cultivation and will grow outside in the UK during the summer;
quite possibly, several of the others will, too. The cultivars of
the commonly grown species (see below) are very variable in size and
colour, so odds on it is one of them.

There has been a fair amount of botanical renaming, too, and I have
never worked out what the situation is between I. nil, I. purpurea,
I. triloba (a synonym of I. nil?) and I. tricolor. I believe that
there are also hybrids. I can state definitely that there is a HELL
of a lot of confusion on the Web and in books over this, and even
quite respectable books conflict badly with each other, so I am in
good company.

I can't really help with this, but after a little digging. I find that =

The true Ipomoea triloba L. is more closely related to the sweet potato
(subg. Batatas) than to the other species. Ipomoea triloba Thunb. Is
given by IPNI (http://www.ipni.org) as a synonym of Ipomoea hederacea.
(The existence of an Ipomoea purpurea var triloba may add to the
confusion, regardless whether that plant is correctly placed in I.
purpurea.)

I found a citation, requiring JSTOR access, to Austin, Nomenclature of
the Ipomoea nil Complex (Convolvulaceae), Taxon 35(2): 355-358 (1986),
which might clarify things further.

No doubt you'll be skeptical, but a molecular paper on the subject is
Miller et al, Systematics of Ipomoea subgenus Quamoclit (Convolvulaceae)
based on ITS sequence data and a Bayesian phylogenetic analysis, Am. J.
Bot. 91(8): 1208-1218 (2004). See http://wwww.amjbot.org

From then above cited paper, I. hederacea, I. nil and I. indica are a
group of closely related species. (Reading between the lines lumpers may
be tempted to place them in a single species.) Again from the cited
paper, I. hederacea selfs, I. nil is self-compatible and I. indica
self-incompatible.

The resolution of the study isn't great, but the group of species
consisting of I. purpurea, I. pubescens and I. lindheimeri appears to be
separated from the preceding. I. tricolor is more distant. There's no
indication in IPNI of any confusion of the application of the names I.
purpurea and I. tricolor, though the usual lumper/splitter issues may
well apply.

Regards,
Nick Maclaren.



--
Stewart Robert Hinsley

In article ,
Stewart Robert Hinsley writes:
|
| Given that David has confirmed my memory, if it has seed pods, it is
| NOT I. indica. No ifs or buts. I. indica does not set seed.
|
| I found a claim in Am. J. Bot. That I. indica is self-incompatible. If
| this is correct then it is possible that it does set seed in the wild,
| but that the cultivated stock is a single clone.

I found quite a few references of that form in 'academic' places.
As posted earlier, exactly what 'a single clone' means in the context
of vegetatively reproducing plants isn't at all clear :-)

| There has been a fair amount of botanical renaming, too, and I have
| never worked out what the situation is between I. nil, I. purpurea,
| I. triloba (a synonym of I. nil?) and I. tricolor. I believe that
| there are also hybrids. I can state definitely that there is a HELL
| of a lot of confusion on the Web and in books over this, and even
| quite respectable books conflict badly with each other, so I am in
| good company.
|
| I can't really help with this, but after a little digging. I find that =
|
| The true Ipomoea triloba L. is more closely related to the sweet potato
| (subg. Batatas) than to the other species. Ipomoea triloba Thunb. Is
| given by IPNI (http://www.ipni.org) as a synonym of Ipomoea hederacea.
| (The existence of an Ipomoea purpurea var triloba may add to the
| confusion, regardless whether that plant is correctly placed in I.
| purpurea.)
|
| I found a citation, requiring JSTOR access, to Austin, Nomenclature of
| the Ipomoea nil Complex (Convolvulaceae), Taxon 35(2): 355-358 (1986),
| which might clarify things further.
|
| No doubt you'll be skeptical, but a molecular paper on the subject is
| Miller et al, Systematics of Ipomoea subgenus Quamoclit (Convolvulaceae)
| based on ITS sequence data and a Bayesian phylogenetic analysis, Am. J.
| Bot. 91(8): 1208-1218 (2004). See http://wwww.amjbot.org
|
| From then above cited paper, I. hederacea, I. nil and I. indica are a
| group of closely related species. (Reading between the lines lumpers may
| be tempted to place them in a single species.) Again from the cited
| paper, I. hederacea selfs, I. nil is self-compatible and I. indica
| self-incompatible.

I am not so much skeptical as completely croggled! Exactly how a
single species could have variants like that makes me certain that
I am not using the term "species" in the same way as you (or the
authors, if you are quoting them) are!

But I really don't know what a species is in the context of some
plants - blackberries being a good example :-)

Thanks for the references. I must look them up, if only to expand
my mind in peculiar ways ....


Regards,
Nick Maclaren.

In message , Nick Maclaren
writes

In article ,
Stewart Robert Hinsley writes:
|
| Given that David has confirmed my memory, if it has seed pods, it is
| NOT I. indica. No ifs or buts. I. indica does not set seed.
|
| I found a claim in Am. J. Bot. That I. indica is self-incompatible. If
| this is correct then it is possible that it does set seed in the wild,
| but that the cultivated stock is a single clone.

I found quite a few references of that form in 'academic' places.
As posted earlier, exactly what 'a single clone' means in the context
of vegetatively reproducing plants isn't at all clear :-)

| There has been a fair amount of botanical renaming, too, and I have
| never worked out what the situation is between I. nil, I. purpurea,
| I. triloba (a synonym of I. nil?) and I. tricolor. I believe that
| there are also hybrids. I can state definitely that there is a HELL
| of a lot of confusion on the Web and in books over this, and even
| quite respectable books conflict badly with each other, so I am in
| good company.
|
| I can't really help with this, but after a little digging. I find that =
|
| The true Ipomoea triloba L. is more closely related to the sweet potato
| (subg. Batatas) than to the other species. Ipomoea triloba Thunb. Is
| given by IPNI (http://www.ipni.org) as a synonym of Ipomoea hederacea.
| (The existence of an Ipomoea purpurea var triloba may add to the
| confusion, regardless whether that plant is correctly placed in I.
| purpurea.)
|
| I found a citation, requiring JSTOR access, to Austin, Nomenclature of
| the Ipomoea nil Complex (Convolvulaceae), Taxon 35(2): 355-358 (1986),
| which might clarify things further.
|
| No doubt you'll be skeptical, but a molecular paper on the subject is
| Miller et al, Systematics of Ipomoea subgenus Quamoclit (Convolvulaceae)
| based on ITS sequence data and a Bayesian phylogenetic analysis, Am. J.
| Bot. 91(8): 1208-1218 (2004). See http://wwww.amjbot.org
|
| From then above cited paper, I. hederacea, I. nil and I. indica are a
| group of closely related species. (Reading between the lines lumpers may
| be tempted to place them in a single species.) Again from the cited
| paper, I. hederacea selfs, I. nil is self-compatible and I. indica
| self-incompatible.

I am not so much skeptical as completely croggled! Exactly how a
single species could have variants like that makes me certain that
I am not using the term "species" in the same way as you (or the
authors, if you are quoting them) are!

I hope it was obvious that I wasn't quoting them, when I said "reading
between the line".

Another paper, which I perhaps should have mentioned, is Shinners,
Untypification for Ipomoea Nil (L.) Roth, Taxon 14(7): 231-234 (1965).
The little I can see of this seems to imply that Linnaeus didn't
distinguish between I. nil and I. hederacea.

Self-incompatibility is not always absolute, and may vary among the
self-incompatibility alleles in a species. There is precedent - Malus
domestica - for a species containing both self-compatible and
self-incompatible genotypes. And in general, it does not seem
implausible that a population of a species could lose
self-incompatibility with relative ease.

Variation in the ability to self can also occur in a species; it may not
require much morphological change to bring anthers into contact with
stigmas.

The Australian form of Pavonia hastata ("Greevesia cleistocalyx"), which
may be native to Australia, or may be an early introduction, produces
cleistogamous, as well as chasmogamous, flowers, which I have the
impression is not the case for the South American populations, and
therefore might have a higher rate of selfing.

So, while I am not going to argue that they are all a single species -
I'd have to know more about the group first - I don't think that the
difference in breeding system is a disproof of the hypothesis. For
example, Fraxinus excelsior is trioecious, that is some plants have male
flowers, some female flowers and some hermaphrodite flowers. In such a
case regional variation could easily (by loss of one type of flower)
result in dioecious, andromonoecious or gynodioecious populations.

(For an explanation of the jargon see
http://www.malvaceae.info/Biology/SexDistribution.html)

But I really don't know what a species is in the context of some
plants - blackberries being a good example :-)

Thanks for the references. I must look them up, if only to expand
my mind in peculiar ways ....


Regards,
Nick Maclaren.

--
Stewart Robert Hinsley

In article ,
Stewart Robert Hinsley writes:
| |
| | From then above cited paper, I. hederacea, I. nil and I. indica are a
| | group of closely related species. (Reading between the lines lumpers may
| | be tempted to place them in a single species.) Again from the cited
| | paper, I. hederacea selfs, I. nil is self-compatible and I. indica
| | self-incompatible.
|
| I am not so much skeptical as completely croggled! Exactly how a
| single species could have variants like that makes me certain that
| I am not using the term "species" in the same way as you (or the
| authors, if you are quoting them) are!
|
| I hope it was obvious that I wasn't quoting them, when I said "reading
| between the line".

What I meant was I wasn't judging whether that was your opinion or
whether you were merely reporting it! You didn't say :-)

| Another paper, which I perhaps should have mentioned, is Shinners,
| Untypification for Ipomoea Nil (L.) Roth, Taxon 14(7): 231-234 (1965).
| The little I can see of this seems to imply that Linnaeus didn't
| distinguish between I. nil and I. hederacea.

The little I know includes the fact that Ipomoea was one of the genera
where Linnaus's view of the species was very different from the modern
one - and even the pre-DNA modern one. It is surprising that there are
so few.

| Self-incompatibility is not always absolute, and may vary among the
| self-incompatibility alleles in a species. There is precedent - Malus
| domestica - for a species containing both self-compatible and
| self-incompatible genotypes. And in general, it does not seem
| implausible that a population of a species could lose
| self-incompatibility with relative ease.
|
| ...
|
| So, while I am not going to argue that they are all a single species -
| I'd have to know more about the group first - I don't think that the
| difference in breeding system is a disproof of the hypothesis. ...

Yes, indeed, but this brings me onto another reason that I regard
so much of modern plant taxonomy as being the modern equivalent of the
mediaeval theologians spending lifetimes analysing how many angels
could dance on the head of a pin.

Even ignoring the question of monophylogeny, the concept of species is
severely flawed even in vertebrates (as Darwin knew), and almost hopeless
for many plants. Most specialists are aware of this, intellectually,
but far too many fail to draw the obvious conclusion that taking
classification into species too seriously leads directly to madness.
The UK classic is, of course, the bramble :-)

By any reasonable traditional definition, plants as different as
I. indica and any of the species we grow as annuals count as different
species. Just as Malus domestica counts as a single (or small number of
species), despite having SOME essentially incompatible varieties. The
simple fact is that species identity is NOT an equivalence relation!
Without learning a lot more, I can't comment about the others.

I wasn't considering JUST the difference in breeding system, incidentally,
as that would have me committing an intellectual faux pas that I have
accused others of :-)


Regards,
Nick Maclaren.